I am tired of paying for roaming, of being location tracked by my provider and running out of SIM slots.
So I have decided to connect some SIM capabilities to my server and set it up as a sort of proxy that I could access over the internet to send regular SMS and make regular calls through the server.
As far as I can tell it seems to be really complicated to do in linux and I just couldn’t find anyway that would actually support sound over calls.
The only solutions I found right now are to get an old phone (not ideal because of the price, battery and reliability) or use something like
https://www.makerfabs.com/maduino-zero-4g-lte-sim7600.html
Which can be connected to the server on the aux and serial ports. This is not too pricey but still seems like a bit much for my needs.
My question is, are there better ways? Really all I need is SMS and calls.
The only way to connect the SIM number directly is to hack the VoWiFi protocol, but this is not trivial and you still need to install the SIM in the server.
Option 2 - Buy a home SIP2GSM gateway. But it’s quite expensive (by the standards of my region anyway). SMS work with SMPP, calls work too. For goIP I wrote telegram SMS gateway if you interesting: https://github.com/lifespirit/telegram-smpp-bot
Or use SIP providers from your region/operators that support SIP connectivity and then enable full calls redirection. For calls ok.
UPD: or just use VoWiFi from mobile phone. But you need sim slot in phone.
Anyway in all another way you need install asterisk/freeswitch and write config fot it. And linphone client.